When Mary Ellen announces her engagement to Dr. David Spencer, the family is surprised. On the day of their engagement party, they get an unexpected visitor: Dr. Curtis Willard, looking to take over the practice of Dr. Vance. Mary Ellen is soon hired by the new doctor to help him get acquainted with his new patients, and as a result begins to have doubts about her relationship with David. Elsewhere, Jim Bob begins a relationship with Mrs. Brimmer's niece, Patsy.